The god(s) of your world technically have unlimited power, but can only use them by influencing the actions of a mortal organism, like humans. The god(s) can only use as much power as that organism is capable of using.
A living legend who has saved the world several times finally reveals his true name, and it’s something completely embarrassing. However, because he’s saved the world, this embarrassing name become commonplace, and within fifty years there are millions of people named “Riceball” or something along those lines.
Magic that grows in power based on how many people have died in any given area. Battlefields would allow mages to go all-out (more so if more than one battle occurred there), and possibly hospitals. Using magic would consume power proportional to the magic used.
A small, non-sentient organism is the only being capable of magic, and their feats of magic are nothing more than producing food or teleporting away from predators.
As people grow older, they have numerical stats applied to them based on things like intelligence, charisma, and strength. These numbers, rather than the person’s actual abilities or talents, are used to determine the results of tests, elections, and even wars.
Spells have to be downloaded before they can be cast, and their download time depends on the user’s proximity to typically magical locations like tombs and ancient towers and such.
An entire sport dedicated to achieving the most epic of fails, using everything your world has to offer, be it magic, gadgetry, dragons, or anything else.
Space travel is possible via transportation spells, but only one-way.
A mage manages to influence soldiers on both sides of battlefield to drop their spears and fistfight the entire battle.
When living things die, they respawn as a completely random organism. They retain about 25% of their memories, and these come back over the extent of their next life. These memories build over the collective lives.